Blobs is a boardless strategy game in which two players strive to form closed blobs.

Rules

Pieces: Two players, Red and Blue, share a common pool of 48 dice as shown in Figure 1. Each dice has a red neck on the top and blue neck on the bottom.

Figure 1. Blobs dice.

Each die therefore has: 1 x Red face, 1 x Blue face, 4 x Mixed faces.

Figure 2. The three face types.

Start: Red starts by placing a die in the middle of playing area with a Mixed face uppermost.

Figure 3. Starting position.

Play: Players then take turns adding a die adjacent to at least one existing die such that edge colours match all neighbouring edges and corners. Only the uppermost faces need match.

Auto Moves: If a placement creates a concave corner that matches only one dice face in one rotation, then that dice face is also played as part of the move. For example, move m in Figure 4 creates two concave corners that result in auto moves m' (Blue) and m'' (Mixed).

Figure 4. Move m triggers auto moves m' and m''.

Concave corner c does not trigger a further auto move as either of two dice faces can be placed there.

Each move may trigger one or two auto moves.

Aim: A player wins by either surrounding a white blob with their colour or having a blob of their colour surrounded by white. For example, Figure 5 shows a game won by Red (left) and a game won by Blue (right).

Figure 5. Games won by Red and Blue.

A player loses if they achieve a win for the opponent on their move.

The game is drawn if the tiles run out before either player wins.

Notes

A winning or losing blob may be of any size or shape, as long as it is surrounded.

Note, however, that it's not possible to enclose a white blob more complex than a circle with you colour. This is because any white blob with a neck must border both Red and Blue regions, as only the Mixed dice face features a white neck, and a complex white blob will first surround a blob of opponent's colour before you can surround it.

Strategy and Tactics

Tips: Tips of your colour allow you to make potentially dangerous auto moves. Players will generally have more attacking options the more free tips they have available.

Semicircles: Semicircles in white and your colour are the key to the game. White semicircles embedded in your colour may be completed to form a winning circle with a single move that triggers an auto move (as in Figure 4), while semicircles of your colour may be used as threats to direct play.

Forks: Two or more white semicircles embedded in your colour constitute a winning fork. For example, Figure 6 (left) shows two white circles embedded in Red, who can win this game on their next move regardless of whose turn it is. Figure 6 (right) shows two white semicircles, one embedded in each colour, allowing the next player to move to win.

Figure 6. White semicircles: a Red fork (left) and next player wins (right).

Note, however, that two Red or Blue semicircles in your colour do not necessarily constitute a winning fork. The owner can play an auto move to win if it's their turn and the two semicircles are adjacent (Figure 7) but the opponent can foil this play if it's their turn.

Figure 7. A Red fork made with Red semicircles.

Danger Patterns: Auto moves may be used to good effect to set up winning sequences, such as that shown in Figure 8 (Red to move). Red move k sets up a threat that Blue must neutralise immediately with a Red neck to stop this happening. A Red neck to the left fails so Blue's only option is to play a Red neck to right (move l). This allows Red to play move m which triggers auto move m' to set up a winning fork.

Figure 8. Red to move and win.

At this point it would be appropriate for Red to yell "eat semicircular death, you fiend!" and do a victory dance around the room.

Variants

Tumbling Dice: Rather than playing the face of their choice, players must roll a die each turn to determine which face to play.

This introduces a random probabilistic element that could add some extra spice to the game. For example, a player may have to weigh up the risks and benefits of a move that gives them a 2 in 9 chance of winning on their next turn but a 1 in 6 chance of losing if the opponent makes a lucky roll beforehand.

The 1:1:4 bias inherent in the face type distribution becomes important in this variant.

Blobs may be described as a square version of Mambo in which three types of tile (each one a Truchet-like tile) are wrapped into a single cube. Blobs features auto moves as per Mambo but not the null points.